Abstract

Barrier height values of Ni contacts to Mg-doped -type GaN were obtained from current–voltage measurements in this study. The induced deep level defect band through high Mgdoping led to a reduction of the depletion layer width in the near the interface and an increase in the probability of thermionic field emission. It also resulted in an increase in current flow under forward bias condition, which was not analyzed using the thermionic emission model. Further, the calculated barrier height value of Ni contacts to using the thermionic field emission model is in good agreement with the value of obtained from x-ray photoelectron spectroscopymeasurements.

Received 24 May 2004Accepted 07 February 2005Published online 18 March 2005

Acknowledgments:

This project is supported by National Science Council of Taiwan, Republic of China, under Contract No. NSC 93-2215-E-018-005. The XPS was kindly provided from the NTU Instrumentation Center at Taipei National Taiwan University.